Please help with these ASAP and plz explain so I can understand!!!

Which of the following represents a virtual image?

Holes drilled several kilometers into earth’s crust provide direct evidence about earth’s interior in the form of

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.